The present invention relates to fluid-cooled electric cables of the type commonly used, for example, in welding equipment for the purpose of supplying a welding torch or "head" with exceptionally high current. More particularly, this invention relates to improvements in splicing devices of the type used for joining together two lengths of such cables.
Various types of electric welding equipment and electric furnaces require flexible cables capable of carrying high current loads, of the order of hundreds of amperes. Typically, such cables take the form of a braided wire conductor surrounded by a relatively soft and flexible tube or sleeve, such as neoprene. In addition to providing electrical insulation from the wire conductor, such tube serves to maintain a pressurized cooling fluid, usually water, in heat-conducting relationship with the conductor as the latter conducts high current. Electric cables of this type are sold in long lengths, e.g., increments of fifty feet, since they are often required to span long distances between power supply and welding head. Since welding equipment is commonly used in debris-ridden environments containing sharp edges and shapes, the integrity of the welding cable, particularly the fluid containing tube which surrounds the current-carrying conductor, is continually threatened. An inadvertent tug or pull on the cable in the wrong direction can easily result in a tube-tear or puncture and the need to replace the entire cable. Owing to the heavy-duty nature of such cables, it will be appreciated that the replacement cost is high.
In U.S. Pat. No. 1,784,384, issued to J. J. Paugh in 1930, there is disclosed a metal "plug" and tube arrangement which functions to splice together two lengths of water-cooled welding cable of the above type without interrupting the flow of water through the cable. Thus, in the case of a puncture or tear in the cable's fluid conduit, the damaged portion may be cut out of the cable, and two ends of the resulting two cable portions can be coupled together. The plug component simply comprises a cylindrical member having a pair of opposing counter-bored ends. The tube is concentrically arranged within the plug so that an annular space is provided between the outside of the tubular member and the inside surface of the counter-bored region of the plug. The braided wires of each of the cable portions being spliced together are inserted in this annular space between plug and tube wall and secured there by solder or the like. The two confronting ends of the fluid conduit are slid over the plug and secured thereto by a suitable clamp. Thus, the internal tubular member allows cooling fluid to flow thorugh the plug, from one cable length to the other, while the plug, itself being electrically conductive and soldered to the respective electrical conductors of each cable length, provides the electrical continuity from one cable length to the other.
While the above-described apparatus may function well to splice together two lengths of fluid-cooled electrical cable, a reliable splice requires a time-consuming and, in this case, difficult soldering step to achieve the requisite electrical continuity. If one were to attempt to crimp or otherwise mechanically squeeze the respective plug and tube walls together in order to capture the wire conductor therebetween, there would be a risk of closing the tube opening, thereby restricting the flow of fluid therethrough. Moreover, one would risk distorting the circular cross-section of the plug, thereby making a fluid-tight seal between the two fluid conduits quite difficult.